It is an amazing juxtipostion of  Johann Sebastian Bach’s “Jesu, Joy of Man’s Desiring,”  better known as the Christmas carol “Joy to the World,” a celebration of the birth of the Savior and the machines Man has crafted to explore the heavens at Washington’s National Air and Space Museum’s “Milestones of Flight” gallery.

Led by the band’s commander and conductor, Col. Larry H. Lang, the performance begins with a single airman and sitting with his cello, and then builds, swelling to 120 musicians–and then fold in the singers.

The orchestra flash mob is one of the Internet’s hot trends, but it is still surprising that a military band would plug in to the fad so naturally.

This is the Air Force Band’s first-ever flash mob.

Good chance it will not be the last.

Unsuspecting museum visitors including tourists and school groups were astonished as instrumentalists streamed into the gallery from behind airplanes and space capsules, and vocalists burst into song from the Museum’s second floor balcony.